Vulcanizing and coloring wood.



State of and F., or above, 0

kalies,

ment,

gummy WILLIAM AUGUSTUS HALL, OF NEW YORK, N. Y., ASSIGNOR TO AMERICAN MAHOGANY COMPANY, A CORPORATION OF MAINE.

VULCANIZING AND COLORING WOOD.

Specification of Letters Patent.

Patented June so, 1908. I

Application filed May 13, 1907. Serial No. 373,230.

To all whom it may concern:

- Be it known that I, WILLIAM AUGUSTUS HALL, a citizen of'the United States, residing at New York, in the county of New York and New York, have invented or discovered certain new and useful Improvements in the Art of Vulcanizing and Coloring Wood, of which the following is a specification.

This invention relates to the art of treating 10 wood for the purpose of vulcanizing or hardening and coloring the same, so that products resembling some of the higher priced woods, and produced from some of the more common or chea er woods, will result.

5 Attempts iave heretofore been made to darken some of the chea er woods, such as maple and white and ye low birch, for the pur ose of making them resemble some of the i 'her priced woods, such as black cherry black walnut, by boiling the woods in ressure resulting closed receptacles under in temperatures considera ly above 212 This boiling of the wood in water or other liquids at tem )eratures approximating 230 flanges the chemical and physical properties of the wood, so that, in drying, it has a tendency to twist and check or crack. Moreover such boiling process takes out moreor less of what is known in the wood- 30 working trade as the life of the wood, and

renders the same brittle and much less elastic than in its natural state and the present invention or discovery has for its object to obviate these objections so that the wood may 35 be vulcanized or hardened and also colored,

and at the same time be rendered tougher than in its first or normal condition, instead of becoming more brittle. This object is accomplished by adding a suitable alkali or alsuch as ammonium hydroxid orsodiurn hydroxid, to the water in which the wood is boiled, thereby producing weak alkaline solutions which act upon the wood and render it tougher than it was before the treatthe hot alkaline solution also coloring the wood a rich brown. This hardening and toughening effect is due resumably to two causes; first,,to a semi-so ution of the ligneous matter in the wood, forming an adhesive,

mass which more closely binds together the cellulose structure of the wood; a' d, second, to the hydrolytic action of the alkali or alkalies on the lignin-cellulose composition, similar to the action known as mercerizing.

I have discovered that woods which are penetrated with solutions of ammonium hydroxid and then boiled at temperatures exceeding 212 F., become very much tougher and harder than the natural woods, but have a greater tendency to warp and check or crack than the woods which have been simply boiled in water, and the woods thus boiled in the ammonium hydroxid solution are rendered very much darker in shade than when simply boiled in water, articularly in the heart portions of the woo I have also discovered that woods treated with sodium hydroxid have become as hard and tough, and even more so, as those treated with ammonium hydroxid, but with much less tendency to war or twist and crack or check; but it has been ound that it is well nigh impossible to thoroughly permeate the wood treated with the sodium hydroxid solution, even by the best of vacuum and pressure processes; presumably for the reason that a gelatinizing occurs on or near the surface of the wood which largely prevents further enetration of the sodlum hydroxid solution into the wood; so that the sodium hydroxid solution produces, when the wood is dried, what may be termed case hardening on the outer parts of the wood, without vulcanizing and coloring the wood throughout. While, from one point of view, the sodium hydroxid solution is more desirable than the ammonium hydroxid solution, in that it better toughens and hardens the wood and leaves it with much less tendency to warp, twist and check or crack, it is much less desirable from another point of view, in that it is practically impossible to crmeate the wood throughout with the sodium hydroxid solution. I have discovered, however, that a mixture of sodium and ammonium hydroxids results in a solution with excellent penetrating qualities; and that the presence of the sodium hydroxid revents, to a great extent, the checking an the ammonium hydroxid. It is by this combination of the two hydroxide that I obtain the good effects of each without the ill effects of either, and am able to color the wood to the fine rich by ammonia, and at the same time avoid the astringent characteristics of the ammonia which cause undue shrinking when the wood is dried, and which produce the warping and warping tendencies of 0 brown shades produced 1 5 mixed solution the ammonium hydroxid lessens the extreme 'hydrolytic action of the sodium hydroxid and enables the solution to com letely penetrate the Wood.

T e solution which I find to roduce the best results in the treatment of t e Wood for the purpose of vulcanizing and coloring the same, as above referred to, comprises, 1n its most desirable proportions, about 3 lbs. of sodium hydroxid to 2 gals. 26% ammonium hydroxid and gals. of Water.

In carr 'ng the invention into effect the wood is rst thoroughly driedand is then preferably subjected to the action of a vacuum in a closed receptacle of above 25 inches of mercury, for the urpose of removing the air from the wood and renderin it absorbent. The alkaline solution, pre erably comprising the ingredients in the proportion just above mentioned, is then drawn or forced into the receptacle and a high hydraulic or other pressure is then preferably a plied to force the alkaline solution into and t roughout the body of the wood, although this pressure is not really necessary unless the wood being treated is more than i of an inch in thickness, but if the wood be an inch or more in thickness it is absolutely necessary,

in order that the Wood may be penetrated throughout by the alkaline solution. The wood is boiled for several hours (the time -varying according to the thickness of the wood) in a closed receptacle either before or after the hydraulic ressure is applied, but preferably afterward s By practicing the invention or discovery, as above described, very tough and hard products of artificially colored wood, with rich brown shades,- will beproduced. Although, in the practice of the invention or discovery, an alkaline solution comprising sodium and ammonium hydroxids is preferably employed, the invention or discovery is not to be understood as being limited to these particular alkalies or hydroxids; as potassium hydroxid and some other alkaline salts consistin in boiling the same in a closed rea ceptacle 1n an alkaline solution comprising a. mixture of sodium and ammonium hydroxids, in substantially the proportions stated. I

2. The herein described recess of treating Wood, for the purpose of co oring and vulcans izing the same, consisting in first thoroughly drying the wood, then subjecting the dried wood, in a closed receptacle, to the action'of a vacuum for the purpose of removing the air therefrom and renderin the same absorb- 7' ent, and subsequently forcing an alkaline solution into'and throughout the wood, by high pressure, and boiling the wood in said solution.

wood for the purpose of co oring and vulcanizing the same, consisting in first thoroughly drying the Wood, then subjecting the dried wood, in a closed receptacle, to the action of a vacuum, for the purpose of removing the air therefrom and rendering the same absorbent, and subsequently forcing an alkaline solution, consisting of a mixture of sodium and ammonium hydroxide, into and throughout the body of the Wood, by high pressure, and boiling the wood in said solution.

In testimony whereof I aflix my signature,

'in presence of two Witnesses.

WILLIAM Witnesses:

JOHN C. McCUsKER,

C. M. SWEENEY.

AUGUSTUS HALL.

3. The herein described recess oftreating 7: 

